View Full Version : "One design" ATC 70 racing

01-09-2013, 10:07 PM
Forgive me if I am copying anyone else's idea. I know there are plenty of atc70 racing clubs out there. Posting some examples, forgive me if I don't know who you are. I don't know the rules you guys race with, but what I am imposing is a one design class that we all agree to build and race with. Like a club, and if we happen to be at the same place, we could all race together on fairly even builds. What I was thinking was just to agree to one motor, and one axle width, then the rest you could do what you want. A motor like the piranah 155 HO, or something else more affordable. I've seen some quick 140's in youtube videos.

I have been searching for a 70 for some time now, and I got one. So I want to build it to be the same as a few of my friends who are thinking the same way. It would be a blast to ice race these or flat track them together. I would love to hear input on the idea.





big specht
01-10-2013, 10:59 PM
I'm glad to see atc 70 flat track racing made it up north :) I think that's me with my old bike racing with rex in the last video

01-11-2013, 11:43 AM
Some friends and I are still trying to get a little race club going. We were going to run a stock class and a modified class like lifan 125 and Honda 110 motors together.
We run two different tracks at two houses. They aren't flat track. We have left and right turns. Small jumps and and hills.
Wanted to run it once a week. Do best lap times and group races. It is mainly for fun. Problem is gettind either enough people for either class. We have 3 bikes with big motors and 3 that are stock.
I think its a good idea you have, but with so many choices of motors and some people not being able to afford the bigger power plants it might not work.
Let me know how it goes and if your ever down my way with a 70 you can race with us.

01-11-2013, 03:13 PM
You would be surprised to find out that many of the 125's will run right with the 140's and 150's with the right rider. I know Flyin Brian beat a host of bigger ones on my modded 125 at Ashtabula last year in the mini class. Let em build what they want and run em..We used to have a stock 81 3 speed 70 that once wound up, would actually run with a 110-125. I think my wife rode it in a TF mx race, and beat some 200x's with it even.

Out of all things Racing, the modded 70's/mini's are truley the class where you can have fun, and throw all the sanctions/rules, and potential drama out the door, and get more interest from others, just seeing the fun you can have with virtually no limits racing. The non suspended trikes only offer so much in handling, and a bigger motor advantage over smaller ones, does not make that much of a difference, as the chassis's seem to level the playing field no matter how much power you put in them. IMO, if you just run what you brung and have a blast doing it, the more turn-outs/riders you can get.

01-11-2013, 07:04 PM
That makes sense. Set a max motor size, then let everyone race. If someone is or thinks they are fast with a smaller motor, then let them run. I have been thinking about it and these guys are correct. It will be hard to get every bike to the same level as people have different budgets. People also have more or less nerve too. I will hunt for a 250cc ATC70. Kidding of course, but I will look for one since I need to buy them for the kids anyway.

01-11-2013, 07:35 PM
I understand about budgets, that's why I was asking what everyone thinks. Let's face it, I am scared to buy one of these Chinese knock off's. I really haven't figured out which one is the most bang for the buck. I mean there is 125's for 179$

Then there is Pirahna 150's for $551.

Then you could easily spend over $1000 on a 182, with race mods. Then it goes from there.

I get what Mosh is saying, and that would be true on small tracks, but on the ice tracks the extra power makes a difference. To give an example, someone on a 70 with like a 140 almost lapped me after just 4 laps while I was on my 110. No matter how I drove it, I was going to lose. If we all had similar trikes, the racing would be closer and a lot more fun. they are only 70's, so who gives a hoot who wins.

Of course this is difficult deciding on a motor, everyone will have a different opinion, and different budget. But we could do it, there is enough of us to start something.

01-11-2013, 07:37 PM
Even the 140 in that second video, which I believe is this one:

Seems to have a lot of grunt.

big specht
01-11-2013, 09:07 PM
We set the size of the motor by the weight of the rider

01-11-2013, 09:20 PM
My all honda 88cc w manual clutch and a fortrax bottom end pulls harder thru the gears than my Lifan125.. the 125 is faster on topend, but you got to run the 88 down..

MIK6/ Mike

01-12-2013, 12:15 AM
That's pretty amazing, but what does building a 88 cost? And can you still get parts easy?

Tri-Z 250
01-12-2013, 12:37 AM
We set the size of the motor by the weight of the rider
Good call...so whats a guy say 255lb get away with running? Do you make the little guys that are overmotored run backpacks with weights?;)shens
To me the 125cc in the extended axle 70 is the funnest thing on the planet that size to ride, IMO.

big specht
01-12-2013, 04:21 PM
I dont remenber you might want to look thru the mad 70's thread I think they posted it up on there

01-14-2013, 09:26 AM
We set the size of the motor by the weight of the rider

Cool, so I get the big motor ;)

01-14-2013, 01:45 PM
i had a 70 with a 90 engine in it blew it up a few to moany times and had to choose what engine to put in it. I didnt want to buy a lifan just because of it being a ching chong knockoff so i shoehorned a klx 110 engine in it. Engine is a 143cc now and is a death machine. I can't imagine putting anything bigger in it, it is a rocket! just a my 2 cents

big specht
01-14-2013, 06:54 PM
My new bike is 146cc but Bigger is not always faster it has alot to do with how your bike is set up and tuned for your riding style